Adults with type 1 diabetes who smoke could have worse HbA1c levels and metabolic outcomes than nonsmokers, new research suggests. Scientists at Medical University of Innsbruck, Austria showed that smoking could also increase the risk of vascular complications in people with type 1 diabetes. Sabine E. Hofer, MD, PhD and colleagues analysed data from the T1D Exchange Registry in the United States and the Prospective Diabetes Follow-up Registry in Germany and Austria. In total, this cohort included 20,405 adults with type 1 diabetes who had the condition for at least one year. The study team sought to determine the association between smoking status and metabolic outcomes, with participants defined as smokers if they smoked at least one cigarette per day. The other groups included former smokers and never smokers. Increased HbA1c levels Those who smoked were found to have significantly higher HbA1c levels compared to nonsmokers (70 vs 62 mmol/mol). This association still existed after adjustment for sex, age, and diabetes duration. Smokers were also found to have higher levels of triglycerides and LDL cholesterol compared to nonsmokers. “Our data clearly show higher HbA1c and additional unfavourable lipid profiles in patients with [type 1 diabetes] who smoke,” said the researchers. “We observed a significantly higher number of former smokers in the [United States], implying that interventions to reduce tobacco consumption and smoke-free policies have been more successful in the [United States] compared with Europe.” The study was published in the online journal Diabetes Care. It is recommended to quit smoking if you have diabetes as this will lower your risk of developing long-term complications such as heart disease. Read our tips on how to quit smoking.